R. Ferdinand P-E. Bernaudin, P. Bosland, M. Di Giacomo, Y. Gómez Martínez, G. Olry
1978 Today Tomorrow
Strong demand of radioactive beams by the nuclear and astrophysics communities (Prod) Establish a bridge between nuclei-nuclei interaction and underlying quarks and gluons Produce RIB using the ISOL technique 10 9 pps for 132Sn, 10 10 pps for 92Kr Research with high intensity stable beams (S3) low-energy in-flight techniques using stable beam N=Z, nuclear structure study through collisions, chemical and physical studies of heavy and super heavy elements, Ions-ions collisions Neutron for science (NFS) and interdisciplinary studies : Production of an intense neutron flux Material irradiation, cross section measurements (for ADS, generation IV, fusion etc…)
light-ion stable beams + SPIRAL1 with heavy-ion stable beams new beams ! RIB induced reactions Production of radioactive beams/targets: SHE (n, ), (p,n) etc. N=Z Isol+In-flight Transfermiums Fusion reaction with n-rich beams Fission products (with converter) Fission products (without converter) Deep Inelastic Reactions with RIB/stable beams High Intensity Light RIB Energy range of SPIRAL2 RIB : ≤ 60keV and 1 -20 MeV/nucl.
Nominal operation of GANIL/SPIRAL2: Phase1 objective: up to 79 weeks/y of stable-ion beams Increasing the stable beam power by a factor up to 53 weeks/y of RIB 10 to 100 up to 5 beams (2 RIB) simultaneously DESIR (very low 800-900 users energy studies) A/q=2 ECR source p, d, 3,4 He, 5mA A/q=3 ECR source Up to 1mA Phase 1 Phase 2 Phase2 objectives: - Increasing the RIB production by a factor 10 to 1000 - Extend the range of beams nuclei Z>40 A>80
Total length: 65 m (without HE lines) Particles H + 3 He 2+ D + Ions Slow (LEBT) and Fast Chopper (MEBT) RFQ (1/1, 1/2, 1/3) & 3 re-bunchers Q/A 1 2/3 1/2 1/3 1/6 12 QWR beta 0.07 (12 cryomodules) I (mA) max. 5 5 5 1 1 14 (+2) QWR beta 0.12 (7+1 cryomodules) W O max. 33 24 20 15 9 1.1 kW Helium Liquifier (4.5 K) (MeV/A) Room Temperature Quadrupoles CW max. beam Solid State RF amplifiers (10 & 20 KW) 165 180 200 44 48 power (KW) 6.5 MV/m max E acc = V acc /( β opt λ ) with V acc =∫ E z (z)e iωz /c dz . 6
Huge number of different beams Intensities (diagnostics), energies (cavities and RF), particles (facility operation, safety) Accelerator components Heavy Ion source (1mA Ar 12+ ) RFQ transmission + frequency (88MHz) tolerances Cryomodules 6.5 MV/m in operation Separate vacuum, compactness (transition and helium buffer) Safety issues Losses < 1W/m Tunnel accessibility, Nuclear ventilation earthquake RIB Production module (primary beam : D + , 200kW) Reliability, maintenance Connections UCx oven D n Converter and delay window
Beta 0.07 energy section Beta 0.12 energy section L 32 m Cryomodule A B Valve-to-valve length [mm] 610 1360 # cavities 12 14 f [MHz] 88.05 88.05 opt 0.07 0.12 Epk/Ea 5.36 4.76 Bpk/Ea [mT/MV/m] 8.70 9.35 r/Q [ ] 599 515 Vacc @ 6.5 MV/m & opt 1.55 2.66 Lacc [m] 0.24 0.41 Cryomodule A Cryomodule B Power coupler Beam tube [mm] 38 44 CEA Saclay IPN Orsay LPSC Grenoble 13
P cav < 10 W @ 6.5 MV/m P Cu ~ 1.5 W @ 6.5 MV/m Stainless steel LHe tank Bulk niobium cavity Tuning system applicators Indium gasket f [MHz] 88.05 opt 0.07 E pk /E acc 5.36 Removable bottom B pk /E acc [mT/(MV/m)] 8.70 plate (in copper) r/Q [ ] 599 End plate sealing V acc @ 6.5 MV/m & opt 1.55 Motivation: numerous leakage with helicoflex seal L acc [m] 0.24 Advantage: no leaks anymore, slightly better Q 0 Beam tube [mm] 38 Disadvantage: indium is difficult to remove/clean no HPR after VC
Porous metallic plates (“ Poral ”) in pyramidal shape to optimize helium phase separation + return of helium gas displaced for the thermosiphon Motivation: cryogenic instability, helium level regulation difficult Advantage: cryogenic system is now stable, no more “fake” losses Former connection
All cavities received and tested The spare cavity under repair Copper bottom cap and Indium seal Qi : 5,8.10 5 to 1.1.10 6 Qt : 2,4.10 10 to 5.3.10 10 1,E+10 AZ1 AZ2 AS3 AZ4 Q 0 Zanon and SDMS cavities AS7 AS9 AZ10 1,E+09 AS11 AZ12 AS13 1,E+08 1,E+07 0 1 2 3 4 5 6 7 8 9 10 11 12 E acc (MV/m) QWR A ( =0.07) 21 L acc = β l = 0.24m
1 Beta 0.07 QWR per module Tuning system Power coupler 23
Vacuum vessel Magnetic shield (against the vacuum vessel wall) Cryogenic connections (towards valves box) Super-insulation Tuning system Beam gate valves (metal) 60K thermal screen Specifications: • Separate vacuum 610 mm • Static losses < 11 W • Dynamic losses < 10 W per cavity for E acc 6.5 MV/m
RF conditioning is required (coupler extremity) Room temperature up to 10kW, cw ( 1h) Again at 4.5k, cavity detuned Cavity tuned up to 4 MV/m in CW mode, limited by RX kind of High Peak Power Processing, 50Hz Duty cycle is limited to level accepted by the cryogenics ( 15 to 30%) RF power to ignite the electronic emission sites, at the quench limit. Rise progressively Pi up to full power (8-10kW), field at the end up to 8 to 10MV/m Thanks to Luc Maurice
Decreasing 2ms /6db Pt : 8MV/m RX Pi : 3kW For CMA3 pulse operation last 30 min from 4 to 8MV/m
Sequential cooling (thermal shield cooled down first during 1 day) Cavity cool down 250K 4K: < 1 hour (except cavity bottom) Mean static losses: 4.3 W (Specs <8.5W) Mean total CM losses @ 6.5MV/m : 15 W (Specs <20.5 W) Mean total CM losses @ 7.8MV/m : 30 W LLRF system successfully tested on cryomodule, very low µphonics Stiff cavities -1.3 Hz/mbar 120 50 45 100 Liquid He level (mm) 40 35 GHe flow (m 3 /H) 80 He Gaz flow (m3/H) 30 LHe (%) 60 25 4.4 W 20 40 15 4.1 W 10 20 5 0 0 0 5 10 15 20 25 30 35 40 45 50 time (min) 27
CMA test stand in Saclay 28
Cavities : All cavities qualified spare cavity being repaired by manufacturer Cryostats : Eight cryomodules assembled, 6 tested All CMA to be delivered to GANIL before end 2013 29
Cryogenics tubing port CTS and plunger Specifications: Cryostat helium buffer • Separate vacuum Thermal shield • Alignment from outside Magnetic • Static losses < 11 W shield • Dynamic losses < 10 W per Beam tube metalic valves cavity for E acc 6.5 MV/m Beam axis Power couplers 31
Tuning system f [MHz] 88.05 opt 0.12 • Welded bottom E pk /E acc 4.76 end B pk /E acc [mT/(MV/m)] 9.35 • Titanium LHe tank r/Q [ ] 515 2.66 • Plunger based V acc @ 6.5 MV/m & opt tuning system L acc [m] 0.41 Beam tube [mm] 44 32
Company RI GmbH selected for the 16 series cavities (14 needed at first) All cavities delivered All cavities tested, with specs OK Chemistry done in Orsay Only one cavity needed repair (too high in frequency at first, local chemistry in H field area) Cryostats all manufactured by SDMS
1.E+10 Q 0 3.7 W MB04 avant étuvage 8.4 W MB04 après étuvage 1.E+09 1.E+08 0 1 2 3 4 5 6 7 8 9 10 11 12 E acc (MV/m) L acc = β l = 0.41 m 2 days @ 110°C 34
2011 tests: pollution (X rays near cavity >100 mSv/h) Latest test showed good results (rust parts and new coupler preparations) Had some concern with “negative backlash” of tuning system: due to mechanics. Solved. Cryogenic consumption in W!! Cryogenic consumption!! Cavity frequency Change of direction Static losses ~35W Motor drive 35
Cavities : All cavities have been qualified without and with plunger Cryostats : Two cryomodules validated with respect to RF, vacuum and cryogenic loss requirements (one is misaligned) One cryomodule already delivered to GANIL All cryomodules B to be delivered to GANIL before sept .2014 All difficulties solves (hopefully!) 36
38
Check of dust particles rate for all components connected to the cavity Cryomodules A: no more HPR rinsing between VC test and CM HPR rinsing and beam assembly (slow refilling with vacuum sealing in filtered N) ISO 4 clean rooms (Coupler prepared in LPSC clean room)
Validated up to 40kW CW in traveling wave 20 were conditioned up to 20kW CW in standing wave (open circuit) Time is now shorter than one hour Plan to finish the preparation of all the couplers by Christmas 2013 41
42
• Same coupler for both cavities • Different coupling (5.5 10 5 and 1.0 10 6 ) achieved by a different antenna penetration depth Hollow antenna Ceramic window Vacuum pumping (uncoated) port Electrons pickup Ceramic (air) cooling pipe
E up to 12 MV/m (CMA) at the antenna extremity for nominal accelerating gradient (accelerating gap area around 37 MV/m) Static + dynamic losses 1.0 to 1.5 W (as computed and as measured) No MP above 150 W of forward power
48
BPM Room for a pick up Beam axis Many functions: correct the position (QWR, errors) transverse tuning of the Linac using the quadripolar moments Beam phase measurem. Time of flight measurement Bunch Extension Monitor (4 first meshes) 49
clean room (iso5) assembly Connexion test with a CMA on alignment bench Tunnel installation under laminar flow (iso5)
Recommend
More recommend
